This invention relates to a switching voltage regulator circuit. More particularly, the present invention relates to a switching voltage regulator circuit that can provide multiple independently regulated voltage outputs using time sequencing techniques.
There are increasing demands in the electronics industry for power supplies that provide multiple regulated outputs. In the past, most integrated circuits operated at 5 volts. Now, the standard operating voltage for an integrated circuit is 3.3 volts. In the future, newer integrated circuits are expected to operate at 2.5 volts and below. With various integrated circuits and electronic devices operating at different voltages, the ability to supply efficiently regulated multiple voltage outputs from a single power supply has become increasingly more important.
One approach to obtaining multiple regulated voltages from a conventional power supply has been to construct several independent regulators, each controlling its corresponding output. Another approach has been to connect to the outputs of a first stage regulator separate "post-regulators" (usually linear regulators) for each different voltage output desired. However, both of these approaches require additional components, which add cost and consume power and space, and thereby lower the efficiency of the power supply. A further approach has been to use a multiple winding technique or charge pump circuit to generate additional voltage outputs from a single regulated output. Here, the disadvantage is that the auxiliary outputs are not directly regulated. As a result, the auxiliary outputs may fluctuate depending on load and line variations.
In view of the foregoing, it would be desirable to provide a switching voltage regulator circuit having multiple independently regulated outputs, which is capable of efficient operation.
It would also be desirable to provide a switching voltage regulator circuit having multiple independently regulated outputs, which operates over a broad range of input voltages and output requirements.